9
Answer: ASet 2: Circles (Beginner)
Explanation
PROBLEM
A circle has radius 9. What is its area? (Express answer as a number times pi)
A circle has radius 9. What is its area? (Express answer as a number times pi)
A.✓ Correct
81pi
B.
90pi
C.
18pi
D.
9pi
Detailed Explanation
Choice A is the best answer. Area = pi times r squared = pi times 9 squared = 81pi
Why others are wrong:
B: 90pi is incorrect because it does not satisfy the equation.
C: 18pi is incorrect because it does not satisfy the equation.
D: 9pi is incorrect because it does not satisfy the equation.